ppl
Building amps and assuring water resistance.
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Audio power Amplifiers rated over 5 watts per channel are tested under the FTC rule governing Power ratings of Power Amplifiers for High Fidelity use. This was done because of the lack of available testing standards regarding power output ratings. Prior to 1974 manufactures were free to use what ever power rating would give the Biggest numbers and thus a 10 watt amplifier could easily be rated at 200 watts. A small foot note would sometimes accompany the ratings like IPP
(Instantaneous Peak Power) IHF (Institute of High fidelity) EIA (Electronic industries association)
The Distortion was also tested at whatever frequency that gave the best numbers. This was most often at 1 KHz. Also frequency response was also tested at whatever method gave the best results. This made meaningful comparisons between Power amplifiers meaningless and thus consumers including me petitioned the Government to set up standards so consumers would not be ripped off by Audio equipment manufactures, And to allow direct comparisons between Audio equipment manufactures.
The government did intervene on behalf of consumers to define standards and these standards were later relaxed as Audio equipment manufactures complained and the EIA lobbied congress on the industry behalf so as to allow a less stringent testing method. Audio power Amplifiers had to be specified as to the Minimum Continuous power output over a specified bandwidth and a defined resistive load and prior to any testing the Amp has to be run at one third power for one hour. The first EIA complaint was the FTC Rule specifying that prior to testing the Amp had to be operated at one third power for one hour so as to get the Amp up to its hottest operating temperature. One third powers generally generate the most heat in a Class b or Class AB output stage due to the large voltage across the conducting transistor. This was later relaxed to one hour accumulated time. See
http://www.ftc.gov/opa/2000/12/amprule.htm
http://www.electronixwarehouse.com/e...er-ratings.htm
http://www.soundwise.org/gethelp/specratings.htm
http://www.ftc.gov/os/2000/12/amplifierrulenotice.pdf
This was finally amended to operation at one eighth power output so as to accommodate the inadequate heat sinking and cheep underpowered power supplies the new Multi-channel Home Theater Amplifiers are now using. THX certified are meaningless and just hype.
Change could be on they way for the better as more and more people require measurements that better relate to how an Amplifier actual sounds
http://www.aesitalia.org/Materiale/a...r%20thesis.pdf
http://www.crownmagnetics.com/pdf_files/f1p73sc.pdf
http://www.qscaudio.com/press/in_news/cssbypq.htm
The definitive standard for testing of Audio Amplifiers as the HP system. this microprocessor based Interments specifications and the generally accepted method of testing Audio equipment is available hear.
http://www.testequipmentdepot.com/us...zers/8903a.htm
(Instantaneous Peak Power) IHF (Institute of High fidelity) EIA (Electronic industries association)
The Distortion was also tested at whatever frequency that gave the best numbers. This was most often at 1 KHz. Also frequency response was also tested at whatever method gave the best results. This made meaningful comparisons between Power amplifiers meaningless and thus consumers including me petitioned the Government to set up standards so consumers would not be ripped off by Audio equipment manufactures, And to allow direct comparisons between Audio equipment manufactures.
The government did intervene on behalf of consumers to define standards and these standards were later relaxed as Audio equipment manufactures complained and the EIA lobbied congress on the industry behalf so as to allow a less stringent testing method. Audio power Amplifiers had to be specified as to the Minimum Continuous power output over a specified bandwidth and a defined resistive load and prior to any testing the Amp has to be run at one third power for one hour. The first EIA complaint was the FTC Rule specifying that prior to testing the Amp had to be operated at one third power for one hour so as to get the Amp up to its hottest operating temperature. One third powers generally generate the most heat in a Class b or Class AB output stage due to the large voltage across the conducting transistor. This was later relaxed to one hour accumulated time. See
http://www.ftc.gov/opa/2000/12/amprule.htm
http://www.electronixwarehouse.com/e...er-ratings.htm
http://www.soundwise.org/gethelp/specratings.htm
http://www.ftc.gov/os/2000/12/amplifierrulenotice.pdf
This was finally amended to operation at one eighth power output so as to accommodate the inadequate heat sinking and cheep underpowered power supplies the new Multi-channel Home Theater Amplifiers are now using. THX certified are meaningless and just hype.
Change could be on they way for the better as more and more people require measurements that better relate to how an Amplifier actual sounds
http://www.aesitalia.org/Materiale/a...r%20thesis.pdf
http://www.crownmagnetics.com/pdf_files/f1p73sc.pdf
http://www.qscaudio.com/press/in_news/cssbypq.htm
The definitive standard for testing of Audio Amplifiers as the HP system. this microprocessor based Interments specifications and the generally accepted method of testing Audio equipment is available hear.
http://www.testequipmentdepot.com/us...zers/8903a.htm
